Killer Proteins

Chemical structure of a human prion protein molecule (hPrP), which is associated with transmissible spongiform encephalopathies, including Creutzfeldt-Jacob Disease.

Topic

Prion Diseases

Student Exploration

Little prions can cause some big problems

The ability to replicate or reproduce yourself is one of the key characteristics biologists use to define life. Of course, defining life is not a simple thing, and there is more to the definition than just reproduction. That's why scientists go back and forth on whether or not viruses are alive. But did you know there are molecules even smaller than viruses that reproduce themselves? Well, there are; they're called prions and scientists are still working to understand what they are and how they cause disease.

While evidence is increasing to support the idea that prions cause disease, not all scientists are comfortable with the idea of a protein self-replicating or causing disease by itself. The whole idea necessitates a rethinking of disease theory. You can go to this link to find out some of the objections researchers have raised to the prion disease model.

Extension Investigation

Use the resources below to answer the following questions:

How do prions differ from prion proteins? Where in the body do prion proteins occur in the highest concentrations? Do you think this relationship may provide a clue to the role of prion proteins in the body?

How do prions interact with prion proteins? What effect does this have on infected organisms?

What do researchers believe the role of prion proteins in the body may be?

Can people contract "Mad Cow Disease"? Why or why not?

How easy is it to acquire a prion disease from eating an infected animal? Explain this situation as fully as you can.